1. Field of the Invention
The present invention relates to a magnetic recording apparatus for overwriting data on a magnetic recording medium with, for example, a magnetic head mounted on a rotary drum, and more specifically, to a magnetic recording apparatus for stabilizing the recorded state of tracks to which data is overwritten.
2. Description of the Related Art
In magnetic recording apparatuses used in video equipment and magnetic recording apparatuses for writing data for computers, a magnetic head is mounted on the rotary drum of a rotary head unit, and a magnetic tape travels in helical contact with the rotary drum as well as the rotary drum rotates so that a recording operation is carried out to the magnetic tape in a helical scan system.
Among this type of the magnetic recording apparatuses, there is a magnetic recording apparatus which uses a magnetic head having a magnetic gap whose track width Tw is larger than the pitch Tp of tracks recorded on a magnetic tape and overwrites data to the magnetic tape by scanning the magnetic head so that the magnetic gap overwrites the track of the magnetic tape where data is already written.
FIG. 5 is a plan view showing the tape sliding surface of the magnetic head mounted on the rotary drum of the magnetic recording apparatus in an enlarged fashion.
A magnetic gap G is formed to a portion of the tape sliding surface of the magnetic head where cores 1 and 2, which are formed of a magnetic material having a high magnetic permeability, are jointed in confrontation with each other through a non-magnetic material layer. Although the magnetic gap G has an azimuth angle which is inclined by a minute angle with respect to a direction (X-direction) orthogonal to a scanning direction Y, the magnetic gap G is shown at a right angle with respect to the scanning direction Y in this specification.
Symbol Tw denotes the track width of the magnetic gap G. The track width Tw is determined by the depth of core regulating grooves 3, 3 formed to a V-shape on both the right and left sides of the cores 1, 2 at the portion where they are jointed to each other. In a magnetic gap G which is actually formed with an azimuth angle, the track width Tw means the size between both the edges G1-G2 of the inclined magnetic gap G in the track width direction (X-direction). Further, when the distance between the overwrite edge G1 of the magnetic gap G and the side edges of the cores 1, 2 is denoted by symbol L1 and the distance between the other edge G2 and the side edges of the cores 1, 2 is denoted by symbol L2, L1=L2 is established in the magnetic head used in the conventional magnetic recording apparatus and the center of the track width Tw of the magnetic gap G matches the center CL of the cores 1, 2 in the width direction thereof.